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2011 Thermal Guidelines for Liquid Cooled Data Processing Environments (ASHRAE TC 9.9 White Paper)

ASHRAE (announcement via HPAC Engineering) · ASHRAE TC 9.9

The 2011 TC 9.9 white paper that first defined the W1-W5 facility-water classes for liquid-cooled IT; content here is taken from trade-press coverage.

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Overview

This white paper, published by ASHRAE TC 9.9 in 2011, introduced facility-water temperature classes (W1-W5) for liquid-cooled data processing environments. ASHRAE billed it as the first vendor-neutral thermal guideline for such environments and offered it as a free download. It followed the May 2011 air-cooling paper on expanded data center classes.

The classes are defined by facility-water supply temperature: W1 at 2-17 C, W2 at 2-27 C, W3 at 2-32 C, W4 at 2-45 C and W5 above 45 C. Their purpose is to enable full-time economizers for many applications and climates. The paper also covers condensation, operation, water flow rate, pressure, velocity and quality, interface connections and heat-rejection devices.

The information here comes from the trade-press announcement (HPAC); the ASHRAE white paper itself was not read. Class boundaries were later renamed or revised in subsequent editions, so current values should be taken from ASHRAE's liquid cooling guidelines in force.

Key points

  1. Class W1 facility water supply is 2-17 C.
  2. Class W2 is 2-27 C and class W3 is 2-32 C.
  3. Class W4 is 2-45 C and class W5 is above 45 C.
  4. Billed by ASHRAE as the first vendor-neutral thermal guideline for liquid-cooled data processing environments; free download.
  5. The classes are intended to enable full-time economizers for many applications and climates.
  6. Condensation, operation, water flow rate, pressure, velocity and quality are covered.
  7. Interface connections and heat-rejection devices are also addressed.
  8. It followed the May 2011 air-cooling paper on expanded data center classes.

Using it in design

  • In liquid-cooling design, tag facility water loops by W-class, noting that later editions may rename or revise them.
  • Combine with climate data to check whether chiller-less operation is feasible.
  • Include condensation risk and water quality requirements in the facility water specification.

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Who should read it

Mechanical designers choosing facility-water temperature and heat rejection for liquid-cooled IT.

Related standards

  • ASHRAE Liquid Cooling Guidelines

Publication details

Authors
ASHRAE TC 9.9
Publisher
ASHRAE (announcement via HPAC Engineering)
Year
2011
Document number
TC 9.9 White Paper
Document language
English
Source type
Standard
Access
Free to read
Licence
Copyright retained; citation only — the publisher’s terms apply to the original document
Original licence note

Facts from trade-press article (public web page, no open licence); ASHRAE white paper itself not read. Citation only.

Citation

ASHRAE TC 9.9 (2011). 2011 Thermal Guidelines for Liquid Cooled Data Processing Environments (ASHRAE TC 9.9 White Paper). ASHRAE (announcement via HPAC Engineering). TC 9.9 White Paper. https://www.hpac.com/archive/article/20925053/ashrae-introduces-thermal-guidelines-for-liquid-cooled-data-processing-environments

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